This book is about the recognition of new principles in Organic Chemistry. It is also about the discovery and invention of Chemical Reactions. In addition, it deals with the determination of structure by chemical degradation during the epoch when physical methods were not well developed. Also presented are new reagents and new types of functional groups never seen in chemistry before. The overall aim of the collected papers is to show how thought can direct original research and to demonstrate how thought about old or new chemical facts can lead to originality. This is further illuminated by commentaries which Prof Barton has written to accompany these papers.